This disclosure relates to optical articles that can be used to manage light in display devices. The optical articles have a structured surface and can be made by extrusion methods.
Display devices, such as liquid crystal display (LCD) devices, are used in a variety of applications including computer monitors, televisions, hand-held devices, digital still cameras, video cameras, and the like. LCD devices offer several advantages over traditional display devices that employ cathode ray tubes in that they often weigh less, are smaller, and use less power. An LCD panel is typically backlit by one or more linear or point light sources which are optically coupled to the panel such that images are generated.
The use of optical films in display devices is well known. In the case of backlit display devices, a number of different optical films are often used in order to produce a display with high uniform brightness. For example, diffuser films can be positioned between the light sources and the display panel in order to diffuse light propagating from the light sources such that they are not discernible by a viewer positioned on the opposite side of the panel. Diffuser films, however, can undesirably decrease the overall brightness observed at the display panel. Thus, it is often desirable to utilize a brightness enhancing film which can redirect and recycle light thus providing what is sometimes referred to as optical gain.
There is a need for the development of optical articles suitable for use in display devices and that have improved optical and mechanical properties, yet can be manufactured at low cost.